Interface Defect Engineering of a Large‐Scale CVD‐Grown MoS 2 Monolayer via Residual Sodium at the SiO 2 /Si Substrate

Alkali metal halide‐assisted chemical vapor deposition (CVD) methods can produce wafer‐scale uniform monolayer transition metal dichalcogenides (TMDs). Further defect engineering is necessary to obtain high‐performance functional devices. While defect engineering has focused on the surface of the monolayer TMDs or the contact property, interface defect engineering is rare and non‐trivial. Based on a NaCl‐assisted CVD‐grown large‐scale uniform MoS 2 monolayer on SiO 2 /Si substrate, a trace amount of Na cations is present, residing at the SiO 2 substrate during the CVD‐growth process and contributes to the n‐type doping into the supported monolayer MoS 2 . Furthermore, the residual Na cations are electrically moved toward the bottom side of monolayer MoS 2 to passivate the interfacial defects.